"We are not seeking to discourage people from spending time in the sea - an activity which has a lot of benefits in terms of exercise, wellbeing and connecting with nature," Dr Will Gaze, head researcher from University of Exeter Medical School, said.

"It is important that people understand the risks involved so that they can make informed decisions about their bathing and sporting habits.

"We now hope that our results will help policymakers, beach managers and water companies to make evidence-based decisions to improve water quality even further for the benefit of public health."